JP2018189858A - Shake correction device and lens barrel having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shake correction device capable of reducing thickness of a shift unit in an optical axis direction as well as achieving a small diameter in an optical axis direction view, and also to provide a lens barrel having the same.SOLUTION: A coil shape has a linear shape not parallel to a radial direction and a direction orthogonal to the radial direction from an optical axis. An coil inner diameter area accommodates part of a shape of a position sensor that detects a position of a shift member. Thereby, a shift unit can be made thinner in an optical axis direction as well as achieve a small diameter in an optical axis direction view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shake correction apparatus that shifts a lens in a plane orthogonal to an optical axis and a lens barrel having the same in order to correct image shake caused by so-called camera shake in an optical apparatus such as a digital camera or a digital video camera.

  As one of the methods for correcting the optical axis deviation caused by camera shake during shooting, etc. in the lens barrel of optical equipment such as digital cameras, the shake correction lens group is shifted in the plane orthogonal to the optical axis. The method of moving is mentioned.

  Patent Document 1 discloses an example of a drive mechanism that moves a shake correction lens group. This shake correction device is a so-called moving coil type shift unit (vibration correction device), in which a driving magnet is disposed on a fixed base member, and a yoke and a coil are disposed on a movable shift member.

  In addition, three balls are arranged between the base member and the shift member, and the shift member is urged against the base member by the magnetic attraction force acting between the driving magnet and the yoke, thereby holding the ball. . For this reason, when the coil is energized, the shift member shifts in the plane orthogonal to the optical axis while rolling the ball by the Lorentz force acting between the driving magnet and the shake correction is performed. Here, since the movement of the shift member in the optical axis direction is restricted by the ball, the shift member moves only in the plane orthogonal to the optical axis.

JP 2002-196382 A

  In such a shift unit, an example of a method for detecting the position of the shift member in the plane orthogonal to the optical axis is a method using a Hall element. In this case, a magnet is provided on one of the base member and the shift member, and a Hall element for detecting a change in magnetic flux density due to a change in distance from the magnet is provided on the other. Here, it is possible to reduce the thickness of the shift unit in the optical axis direction by disposing the Hall element so that a part of its shape is within the inner diameter range of the coil when viewed in the direction orthogonal to the optical axis.

  However, in this case, there is a limit to downsizing the inner diameter of the coil as long as a space for the Hall element is secured in the inner diameter range of the coil when viewed in the optical axis direction. In particular, when the coil has a substantially rectangular shape having sides parallel to the radiation direction from the optical axis and the radiation orthogonal direction as in the conventional case, the corner portion of the substantially square shape hinders the space saving of the shift unit. . In general, in a substantially cylindrical lens barrel, the shift unit inside the lens barrel also has a shape that fits in a smaller and thinner circular space when viewed in the optical axis direction, which contributes to the miniaturization of the lens barrel. It becomes. However, the corner portion of the coil protrudes in the radial direction from the cylindrical shape, and hinders the reduction in diameter.

  An object of the present invention is to provide a shake correction device capable of reducing the diameter in the optical axis direction while reducing the thickness of the shift unit in the optical axis direction, and a lens barrel having the same.

In order to achieve the above object, a shake correction apparatus according to the present invention includes:
A shift member that holds a shake correction lens and is movable in a plane orthogonal to the optical axis with respect to the apparatus main body is provided, and one of the shift member and the apparatus main body has a drive magnet, and the other has a coil and a yoke. Is a shake correction device that corrects image shake by shifting the shift member by energizing the coil, and there are two sets of shift drive units including the drive magnet, the coil, and the yoke The shift driving units are arranged so as to be orthogonal to each other, and the shape of the coil as viewed in the optical axis direction is a linear shape that is not parallel to the direction axis of the shift movement.

  According to the shake correction apparatus of the present invention, the coil shape has a linear shape that is not parallel to both the radial direction and the orthogonal direction from the optical axis, and the position of the shift member is detected on the inner diameter of the coil. Make a part of the shape fit. Thereby, it is possible to reduce the diameter in the optical axis direction view while reducing the thickness of the shift unit in the optical axis direction.

The disassembled perspective view of the shift unit which is embodiment of this invention Sectional drawing of the lens drive device which has the shift unit which is embodiment of this invention 1 is an electric circuit configuration diagram of an optical apparatus using a lens driving device according to an embodiment of the present invention. Explanatory drawing of the actuator part in the shift unit of embodiment of this invention Explanatory drawing of the generated force in the coil of the shift unit of the embodiment of the present invention The figure which shows another example of the coil shape in embodiment of this invention Explanatory drawing of actuator part in conventional shift unit Explanatory drawing of generated force in conventional shift unit coil

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 2 shows a lens driving device having a bar / sleeve structure according to an embodiment of the present invention. The lens driving device is attached to or used integrally with a photographing device (optical device) such as a video camera or a digital still camera.

  This lens driving device is a lens driving device having a variable magnification optical system with a four-group configuration having convex and concave projections. L1 is a fixed first group lens, L2 is a second group lens that performs a zooming operation by moving in the optical axis direction, L3 is a third group lens that moves in the plane orthogonal to the optical axis and performs shake correction, and L4 Is a fourth group lens that performs a focusing operation by moving in the optical axis direction.

  Reference numeral 1 denotes a first group barrel that holds the first group lens L1, 2 denotes a second group moving frame that holds the second group lens L2, and 3 denotes a shift unit that moves the third group lens L3 in the direction orthogonal to the optical axis (shake correction). (Device) 4 is a fourth group moving frame for holding the fourth group lens L4, and 6 is a CCD holder to which an image pickup device such as a CCD is fixed.

  The first group barrel 1 and the CCD holder 6 are screwed to the fixed barrel 5. Two guide bars (not shown) are positioned and fixed by the fixed cylinder 5 and the CCD holder 6 and support the second group moving frame 2 so as to be movable in the optical axis direction. Similarly, two guide bars (not shown) support the fourth group moving frame 4 so as to be movable in the optical axis direction. The shift unit 3 is positioned on the fixed cylinder 5 and fixed with screws.

  Reference numeral 12 denotes an aperture device that changes the aperture diameter of the optical system. The aperture device changes the aperture diameter by moving two aperture blades in opposite directions.

  The second lens group L2 is driven in the optical axis direction by a zoom motor (not shown) to perform a zooming operation. The zoom motor has a lead screw coaxial with the rotating rotor. A rack attached to the second group moving frame 2 is engaged with the lead screw, and the second group lens L2 is driven in the optical axis direction by the rotation of the rotor.

  Further, the torsion coil springs loosely move the backlashes of the second group moving frame 2, the two guide bars, the rack, and the lead screw, thereby preventing the backlash of these fitting or meshing. The zoom motor is fixed to the fixed cylinder 5 with screws.

  The fourth group lens L4 is driven in the optical axis direction by a focus motor (not shown) to perform a focusing operation. The focus motor has a lead screw coaxial with the rotating rotor. A rack attached to the fourth group moving frame 4 is engaged with the lead screw, and the fourth group lens L4 is driven in the optical axis direction by the rotation of the rotor. In addition, the torsion coil springs loosely move each of the fourth group moving frame 4, the two guide bars, the rack, and the lead screw, thereby preventing backlash of these fitting or meshing.

  The focus motor is fixed to the CCD holder 6 with two screws. The photo interrupter that optically detects the movement of the light shielding portion formed in the second group moving frame 2 in the optical axis direction is a zoom reset switch for detecting that the second group lens L2 is located at the reference position. Used as The photo interrupter that optically detects the movement of the light shielding portion formed in the fourth group moving frame 4 in the optical axis direction is a focus reset switch for detecting that the fourth group lens L4 is located at the reference position. Used as

  Next, the configuration of the shift unit 3 that moves the third lens unit L3 in the direction orthogonal to the optical axis will be described with reference to FIG.

  The third lens unit L3 includes a driving actuator for correcting an image shake due to an angle change in the pitch direction (vertical direction of the lens barrel) and an image shake due to an angle change in the yaw direction (horizontal direction of the lens barrel). It is driven in the plane orthogonal to the optical axis by a driving actuator for correction.

  In the pitch direction and the yaw direction, each actuator is independently driven and controlled based on information from each position sensor and shake detection sensor. The actuator and position sensor for the pitch direction and the actuator and position sensor for the yaw direction are arranged so as to form an angle of 90 degrees with each other. However, since the configuration itself is the same, only the pitch direction will be described below. To do. Unless otherwise specified, a subscript p is attached to elements in the pitch direction, and a subscript y is attached to elements in the yaw direction.

  Reference numeral 22 denotes a shift moving frame that has a function of holding the third lens unit L3 and is displaced in a direction orthogonal to the optical axis in order to correct shake. A magnet 24 serving both for driving and for position detection is press-fitted and held in the shift moving frame 22. By inserting the magnet 24 into the shift moving frame 22 and incorporating it, the relative positional relationship between the shift moving frame 22 and the magnet 24 does not shift after the incorporation. For this reason, the position of the magnet 24 that also functions as a position detection function is determined to be a fixed position with respect to the shift moving frame 22 that holds the third group lens L3, and the position of the third group lens L3 is determined by the magnet 24. Can be accurately detected.

  Reference numeral 20 denotes a ball arranged between the shift base 21 and the metal plate 19, and three balls are arranged around the optical axis in the plane orthogonal to the optical axis. Between the ball 20 and the shift movement frame 22, the metal plate 19 described above is disposed. Due to the presence of the metal plate 19, when the lens barrel receives an impact, the shift moving frame 22, which is a molded part, is dented by the ball 20, and the shift due to wear caused by the long-time shake correction operation drive. Deterioration of the drive characteristics of the unit 3 can be prevented.

  As the material of the metal plate 19, for example, stainless steel is suitable. The ball 20 is rotatably held by a ball folder portion 21 a formed on the shift base 21. The force for reliably bringing the ball 20 into contact with the shift base 21 (the end surface in the optical axis direction of the ball folder portion 21a) and the shift moving frame 22 (the metal plate 19) is between the magnet 24 and the fixed yoke 29. It is the acting adsorption force. The shift movement frame 22 is urged in the direction approaching the shift base 21 by this attracting force, so that the three balls 20 are against the three end portions of the three ball folder portions 21 a and the metal plate 19. Contact in the pressed state.

  Each surface with which the three balls 20 abut is spread in a direction orthogonal to the optical axis of the photographing optical system. Since the nominal diameters of the three balls 20 are the same, the third lens group L3 held by the shift moving frame 22 is suppressed by reducing the positional difference in the optical axis direction between the end faces in the optical axis direction in the three ball folders 21a. Can be moved in the plane orthogonal to the optical axis without causing a tilt with respect to the optical axis. As a material used for these balls, a non-magnetic material such as SUS304 is suitable so as not to be attracted to the magnet.

  Next, position detection of the shift moving frame 22 and the third group lens L3 will be described.

  Reference numeral 27p denotes a hall element that converts a magnetic flux density into an electric signal, and is soldered to a flexible printed cable (hereinafter, FPC) 26. The FPC 26 is positioned and fixed with respect to the shift base 21. The position sensor which detects the position of the shift moving frame 22 and the 3rd group lens L3 is formed by the following structures. When the shift moving frame 22 and the third group lens L3 are driven in the vertical direction or the horizontal direction, a change in the magnetic flux density of the magnet 24p is detected by the Hall element 27p, and an electric signal indicating the change in the magnetic flux density is output. .

  Based on the output of the hall element 27p, a control circuit (not shown) can detect the positions of the shift moving frame 22 and the third group lens L3. The magnet 24p is a drive magnet and is also used as a position detection magnet.

  Next, the actuator for driving the shift movement frame 22 and the third group lens L3 will be described with reference to FIG. In FIG. 4, components other than the shift base 21, the yoke 23, the magnet 24, the hall element 27, the coil 28, and the fixed yoke 29 are not shown. FIG. 4B is an AA cross section shown in FIG. Reference numeral 24p denotes a magnet magnetized in two poles as shown in FIG. 4B, and reference numeral 23p denotes a yoke for closing the magnetic flux on the front side in the optical axis direction of the magnet 24p. The yoke 23p is attracted and fixed to the magnet 24p.

  Reference numeral 28p denotes a coil bonded and fixed to the shift base 21, and 29p denotes a fixed yoke for closing the magnetic flux on the rear side in the optical axis direction of the magnet 24p. The fixed yoke 29p is disposed on the opposite side of the magnet 24p with the coil 28p interposed therebetween, and is held by the shift base 21. These magnet 24p, yoke 23p, fixed yoke 29p, and coil 28p form a magnetic circuit.

  As a material used for these yokes, a magnetic material having a high magnetic permeability, such as SPCC, is suitable. When a current is passed through the coil 28p, a Lorentz force is generated in the direction perpendicular (including substantially perpendicular) to the magnetization boundary of the magnet 24p due to repulsion between the magnetic lines generated in the magnet 24p and the coil 28p. 22 is moved in the direction perpendicular to the optical axis. This is a so-called moving magnet type actuator. Further, as described above, a change in magnetic flux density due to a change in the position of the magnet 24p is detected by the Hall element 27p, and the position of the shift moving frame is detected.

  Since the actuators having such a configuration are arranged in the vertical direction and the horizontal direction as shown in FIG. 1, two optical axis orthogonal directions in which the shift moving frame 22 is orthogonal (including substantially orthogonal) to each other. Can be driven. Further, the shift movement frame 22 can be freely moved within a predetermined range in the plane orthogonal to the optical axis by the drive and synthesis in the vertical direction and the horizontal direction.

  The friction when the shift moving frame 22 moves in the direction perpendicular to the optical axis is between the ball 20 and the metal plate 19 and between the ball 20 and the ball folder portion 21a unless the ball 20 abuts against the wall of the ball folder portion 21a. It is only the rolling friction which occurs between each. Therefore, the shift moving frame 22 holding the third lens unit L3 can move very smoothly in the plane orthogonal to the optical axis, and the amount of movement can be controlled minutely, even though the attracting force acts. It becomes possible. Note that the frictional force can be further reduced by applying lubricating oil to the balls 20.

  FIG. 3 shows an electric circuit configuration of an optical apparatus using the lens driving device according to the embodiment of the present invention.

  In the optical device 120, the subject image formed on the CCD 113 through the lens is subjected to processing such as predetermined amplification and γ correction by the camera signal processing circuit 101. From the video signal that has undergone these predetermined processes, a contrast signal in a predetermined region is extracted through the AF gate 102 or the AE gate 103.

  In particular, the contrast signal that has passed through the AF gate 102 generates one or a plurality of outputs related to the high frequency component by the AF circuit 104. In accordance with the signal level of the AE gate 103, the CPU 105 determines whether or not the exposure is optimal. If it is not optimal, the CPU 105 passes through the aperture shutter drive source 109 to set the drive source at the optimal aperture value or shutter speed. To drive. In the autofocus operation, the CPU 105 drives and controls the focus drive source drive circuit 111 that is a focus drive source so that the output generated by the AF circuit 104 shows a peak.

  Further, in order to obtain an appropriate exposure, the CPU 105 drives the aperture shutter drive source 109 so that the average value of the signal output that has passed through the AE gate 103 is a predetermined value, and the output of the aperture encoder 108 becomes this predetermined value. Control the opening diameter. A focus origin sensor 106 using an encoder such as a photo interrupter detects a reference position for detecting the position of the focus lens group in the optical axis direction. A zoom origin sensor 107 using an encoder such as a photo interrupter detects a reference position for detecting the position of the zoom lens group in the optical axis direction.

  The detection of the shake angle in the photographing apparatus is performed by integrating the output of an angular velocity sensor such as a vibrating gyroscope fixed to the photographing apparatus, for example. The outputs of the pitch direction shake angle detection sensor 114 and the yaw direction shake angle detection sensor 115 are processed by the CPU 105. The pitch coil drive circuit 116 is driven and controlled in accordance with the output from the pitch deflection angle detection sensor 114, and energization control to a pitch coil (not shown) is performed.

  The yaw coil drive circuit 117 is driven and controlled in accordance with the output from the yaw shake angle detection sensor 115, and energization control for a yaw coil (not shown) is performed. With the above control, a shift frame (not shown) shifts in the plane orthogonal to the optical axis. The outputs of the position detection sensor 118 in the pitch direction and the position detection sensor 119 in the yaw direction are processed by the CPU 105. When the correction lens group L3 is shifted, the passing light beam in the lens driving device is bent.

  Therefore, by shifting the correction lens group L3 so as to bend the passing light beam by the amount of bending to be canceled in the direction to cancel the change of the subject image on the CCD 113 that originally occurs due to the shake in the imaging device, the imaging device Even if the image is shaken, a so-called shake correction can be performed in which the formed subject image does not move on the CCD 113.

  The CPU 105 corresponds to the difference between the shake signal of the photographing apparatus obtained by the pitch shake angle detection sensor 114 and the yaw shake angle detection sensor 115 and the shift amount signal obtained from the pitch position detection sensor 118 and the yaw position detection sensor 119. The shift frame 3a is shifted by the pitch coil driving circuit 116 and the yaw coil driving circuit 117 based on the signal obtained by performing amplification and appropriate phase compensation on the signal to be transmitted. By this control, the correction lens unit L3 is positioned and controlled so that the difference signal becomes smaller, and is maintained at the target position.

  Next, an actuator in a conventional shift unit will be described with reference to FIG. In FIG. 7, components other than the shift base 121, the yoke 123, the magnet 124, the Hall element 127, the coil 128, and the fixed yoke 129 are not shown. Moreover, FIG.7 (b) is the AA cross section shown to Fig.7 (a). As shown in FIG. 7B, the Hall element is arranged so that a part of its shape falls within the inner diameter range of the coil. This makes it possible to reduce the thickness of the shift unit in the optical axis direction as compared with the case where the Hall element is disposed outside the inner diameter range of the coil.

  However, as shown in FIG. 7A, on the projection surface in the optical axis direction, one of the corners of the coil protrudes outward in the radial direction with respect to the substantially circular base. It is desirable to reduce the size of the lens barrel. In particular, in a cylindrical lens barrel, it is desirable that the shift unit inside the barrel is smaller and fits in a circular space. However, a part of the shape of the coil is an obstacle.

  On the other hand, as shown in FIG. 5, in the embodiment of the present invention, the coil has a substantially rhombus shape having straight portions 28p1, 28p2, 28p3, and 28p4 that are not parallel to either the pitch direction or the yaw direction. FIG. 5 shows the coil 28p, but the coil 28y has a substantially rhombus shape having straight portions that are not parallel to either the pitch direction or the yaw direction. Thereby, as shown in FIG. 4, it can arrange | position so that the corner | angular part of a coil may not protrude outside the shift base. Similarly to the conventional example of FIG. 7, the Hall element is arranged so that a part of its shape is within the inner diameter range of the coil, thereby making it possible to reduce the thickness of the shift unit. Thus, the shift unit can be accommodated in a circular space having a smaller diameter.

  The generated force in the conventional coil will be described with reference to FIG. FIG. 8 is an enlarged view of the actuator driven in the pitch direction. In FIG. 8, parts other than the magnet 124p and the coil 128p are not shown.

  When a current in the direction shown in FIG. 8 flows through the coil 128p, Lorentz forces f11 and f12 are generated in a side portion orthogonal to the coil pitch direction. Here, the resultant force of the entire coil is F ′ = f11 + f12. The resultant force F drives the shift unit in the pitch direction. Similarly, the shift unit is driven in the yaw direction by the Lorentz force generated by the actuator driven in the yaw direction.

The generated force in the coil according to the embodiment of the present invention will be described with reference to FIG. FIG. 5 is an enlarged view of the actuator driven in the pitch direction. In FIG. 5, components other than the magnet 24p and the coil 28p are not shown. The coil 28p has a shape that does not have a straight line portion parallel to the pitch direction and the yaw direction, but when a current in the direction shown in FIG. 5 flows through the coil 28p, the Lorentz forces f1, f2, f3, and f4 are generated in each straight line portion. Occur. When these Lorentz forces are considered in terms of component force by adding a suffix p to the component in the pitch direction and a suffix y to the component in the yaw direction,
Pitch direction component; Fp = f1p + f2p + f3p + f4p> 0
Yaw direction component; Fy = f1y + f2y + f3y + f4y = 0
It becomes.

  Therefore, in this actuator, a Lorentz force having only a pitch direction component is generated, and the shift unit is driven only in the pitch direction. Similarly, the shift unit is driven in the yaw direction by the Lorentz force generated by the actuator driven in the yaw direction.

  FIG. 6 shows the coil shape of another embodiment. In FIG. 6, components other than the coil 228 ′ and the shift base 221 are not shown.

  As shown in the figure, the shift unit can be accommodated in a circular space having a smaller diameter by forming the coil 228 'into an octagonal shape having straight portions not parallel to the pitch direction and the yaw direction.

  In the above embodiment, the case where the shift moving frame 22 is driven using a moving magnet type actuator has been described. However, in the present invention, the coil may have a shape having a straight portion that is not parallel to the pitch direction and the yaw direction. Accordingly, it goes without saying that the present invention can also be applied to a case where a so-called moving coil type actuator in which the coil 28 and the yoke 29 are arranged on the shift moving frame 22 side and the yoke 23 and the magnet 24 are arranged on the shift base 21 side is used. Yes.

L1 first group lens, L2 second group lens, L3 third group lens (correction lens group),
L4 4th group lens, 1st group barrel, 2nd group moving frame, 3 shift unit,
4 4 group moving frame, 5 fixed cylinder, 6 CCD holder, 12 aperture device,
19 metal plate, 20 balls, 21 shift base,
21a Ball folder, 22 shift frame, 23 yoke,
24 magnets, 26 FPCs, 27 Hall elements, 28 coils,
29 fixed yoke, 101 camera signal processing, 102 AF gate,
103 AE gate, 104 AF circuit, 105 CPU,
106 focus origin sensor, 107 zoom origin sensor,
108 aperture encoder, 109 aperture shutter drive source, 110 zoom drive source,
111 Focus drive source drive circuit, 112 Zoom drive source drive circuit,
113 CCD, 114 pitch angle detection sensor, 115 yaw angle detection sensor,
116 pitch coil drive circuit, 117 yaw coil drive circuit,
118 pitch position detection sensor, 119 yaw position detection sensor,
120 optical equipment, 116 pitch coil drive circuit, 117 yaw coil drive circuit,
118 pitch position detection sensor, 119 yaw position detection sensor, 120 optical device

Claims (3)

A shift member that holds the shake correction lens and is movable in a plane orthogonal to the optical axis with respect to the apparatus main body,
Of the shift member and the apparatus main body, one side holds a driving magnet and the other side holds a coil and a yoke,
A shake correction apparatus that corrects image shake by shifting the shift member by energizing the coil;
There are two sets of shift drive units composed of the drive magnet, the coil, and the yoke,
The shift driving units are arranged to be orthogonal to each other,
The shake correction apparatus according to claim 1, wherein the coil has a linear shape that is not parallel to the direction axis of the shift movement.   The part of the shape of the position sensor that detects the position of the shift member in the plane orthogonal to the optical axis is within the inner diameter of the coil in the optical axis direction view and the optical axis orthogonal direction view. Shake correction device.   A lens barrel having the shake correction device according to claim 1.